Snow skis have been utilized for centuries on vehicles such as sleds and sleighs and more recently on all terrain vehicles, airplanes and snowmobiles. Snow skis have been made from materials such as wood, stone, metal and plastic. Presently, original equipment and aftermarket snowmobile skis are fabricated from crude steel or aluminum with painted or anodized finishes. Aluminum skis are lightweight but are not durable enough for all around trail riding. Steel is preferred for snowmobile skis because of manufacturing ease, low cost and short product life. Steel snowmobile skis wear quickly and last for only about 500-1000 miles with rust and corrosion appearing within the first 100 miles. Paint and powder coat finishes chip and flake off due to impact, vibration and abrasive contact. Snow is inherently filled with all types of debris such as rocks, gravel, sand, sticks and a considerable amount of salt due to operation along roadsides and on road surfaces. As the steel ski wears, the induced drag increases the roughness of the under surface with the ski plowing and churning its way through the snow. As a result, performance and fuel efficiency suffers tremendously not to mention the unattractive appearance of the ski.
Under certain snow conditions, the under surface of a snowmobile ski builds up frozen snow and ice thereon. With such an accumulation, the forward progress of the snowmobile is significantly impeded as a result of the increased resistance of the ski to slide over a snow covered surface. In some cases, the build up of snow and ice on the under surface of a snowmobile ski is so great that the forward progress of the vehicle is substantially prevented. One solution to this problem has been the use of a thin flexible strip of smooth plastic which is attached to the under surface of the snowmobile ski. The plastic does not support the buildup of frozen snow and ice and maintains the under surface of the ski free of snow and ice buildup. However, one problem associated with this solution is the rapid wear of the plastic strip. As a result, the plastic under surface strip is used only when temperature and snow conditions are encountered which promote the buildup of frozen snow and ice on the under surface of the snowmobile ski. Not only is the plastic strip subject to rapid wear, but the need for the operator to attach and remove the plastic strip depending on existing snow conditions is both time consuming and annoying.
Another problem associated with vehicular snow skis is the shape of the under surface. Present lateral construction of the under surface of the ski is flat which promotes wear of the under surface over rough terrains. The front end tip of the ski is curled with a fixed curvature for engaging the snow and setting the front suspension of the vehicle. With a fixed curvature, the suspension of the vehicle may be set for one type of snow condition such as shallow or dry hard packed snow but is not adapted for efficient use in deep snow where the progress of the vehicle may be seriously impeded. Typically, the curvature is set in a neutral position which is neither good or bad for any snow condition. However, this neutral position doe not provide an optimum setting particularly for high performance or competition applications.
With flat-bottomed snow skis, a longitudinally positioned steering or wear bar has been added to the under surface to provide directional steering of the ski. However, this bar wears as quickly, if not more so, than that of the under surface of the ski with loss of directional control as the steering bar is worn. The longitudinal under surface of the ski has also been formed into a convex or bowed shape to improve steerability, but again the wear at the center of the ski is significantly increased.